The book of Jonah heavily implies that the acceptance of Jesus isn't necessary for salvation.
I'm pretty sure we all know the story of Jonah. Ninevah being the worst city on the planet, God wants Jonah to warn them. He doesn't want to, runs away, gets eaten by a fish, eventually prophesies, the people repent, God forgives, the city isn't destroyed, God is good.
But the fact that God forgave them is very, very important.
Nowhere in the Book of Jonah does it imply that the sacrifice of innocent life was a requirement for God to forgive the Ninevites.
They repented, they humbled themselves, they fasted. But they did not kill, shown by the actual verses:
"6 When Jonah’s warning reached the king of Nineveh, he rose from his throne, took off his royal robes, covered himself with sackcloth and sat down in the dust. 7 This is the proclamation he issued in Nineveh:
“By the decree of the king and his nobles:
Do not let people or animals, herds or flocks, taste anything; do not let them eat or drink. 8 But let people and animals be covered with sackcloth. Let everyone call urgently on God. Let them give up their evil ways and their violence. 9 Who knows? God may yet relent and with compassion turn from his fierce anger so that we will not perish.”
10 When God saw what they did and how they turned from their evil ways, he relented and did not bring on them the destruction he had threatened."
God still forgave them. Which makes Jonah very angry. They have a little debate, and it ends with God saying:
" And should I not have concern for the great city of Nineveh,in which there are more than a hundred and twenty thousand people who cannot tell their right hand from their left—and also many animals?” "
It shows that God has concern for those who do not know him, and that can be delved into another day. The point is that this was a time where Jesus hadn't existed yet, and supposedly the only way through forgiveness was through the sacrifice of an innocent life.
But there were no mass killings in Ninevah and God still forgave them.
Meaning that God can forgive without the need for death.
Meaning that, according to the bible, people who believe in God do not need Jesus.